General Papers ARKIVOC 2005 (xv) 30-38

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1 General Papers ARKIVC 2005 (xv) Polycyclic heterocycles with acidic - group, VI. 1 The synthesis of some polycyclic heterocyclic compounds related to 3-phenyl-1,2-dihydroquinoxaline-2-one Iveta Fryšová*, Jan Slouka, and Tomáš Gucký Department of rganic Chemistry, Palacký University, Tř. Svobody 8, lomouc, Czech Republic frysova@orgchem.upol.cz (received 02 Jul 05 accepted 13 Aug 05 published on the web 17 Aug 05) Abstract This work deals with the study of the reactivity of substituted 3-(2-aminophenyl)-1,2-dihydroquinoxaline-2-ones (4a, 4b). 3-(2-Amino-4-fluorophenyl)-1,2-dihydroquinoxaline-2-one (4a) was prepared by the reaction of 6-fluoro--acetylisatin (2a) with 1,2-diaminobenzene and further hydrolysis of the acetyl group. Compound 4b was prepared directly by the reaction of 7- nitroisatin (1b) with 1,2-diaminobenzene. The cyclization reaction of compounds 4a, 4b in PCl 3 afforded indolo[2,3-b]quinoxalines 7a, 7b. Intramolecular splitting cyclizations of diazonium salts 5a, 5b led to [1]benzofuro[2,3-b]quinoxalines (6a, 6b) and azo-coupling reactions of diazonium salts 5a with ethyl cyanoacetylcarbamate and malonodinitrile gave arylhydrazones 9a and 10a. By the diazotization of amine 4b we were able to isolate diazotate 8b in sodium acetate solution. The azo- coupling reactions of diazotate 8b with ethyl cyanoacetyl carbamate and malonodinitrile gave the arylhydrazones 9b and 10b. These arylhydrazones were then transformed into 1,3-diaminopyrazoles (11a, 11b) and 6-azauracils (12a, 12b). Keywords: 3-Substituted 1,2-dihydroquinoxaline-2-ones, 1-aryl-6-azauracils, heterocycles with acidic - groups Introduction There have been found a large number of biologically active compounds among polycyclic heterocyclic compounds with free rotation of their rings. 2-8 This group of heterocycles includes with surprise some transforming growth factor 9, 10 11, 12 inhibitors, reverse transcriptase, dihydrofolate reductase 13 14, 15 and cyclin-dependent kinase inhibitors. The structure of most cyclin- dependent kinase inhibitors is related to purine, 15 however recently the same activity was found for a few compounds with completely different structure. ISS Page 30

2 General Papers ARKIVC 2005 (xv) This fact inspired us to prepare other polycyclic heterocyclic compounds bearing quinoxaline 16, 17 and [1,2,4]triazine or pyrazole ring in their structure. Results and Discussion The target of this work is the study of reactivity of some substituted 3-(2-aminophenyl)-1,2- dihydroquinoxaline-2-ones and their use for preparation of condensed heterocyclic compounds which bear quinoxaline ring as well as non condensed heterocyclic compounds comprising quinoxaline and [1,2,4]-triazine or pyrazole ring. 1 3 C C R 5 =R 6 =-C R 5 =-CCC 2 5, R 6 =-C R5 R6 8 7 a) R 1 = F, R 2 = b) R 1 =, R 2 = 2 C Scheme 1 The key intermediate 4a was prepared easily in a multistep reaction from the corresponding isatin 1a. 18,19 The cyclocondensation reaction of isatin 1a with 1,2-diaminobenzene was not successful; however, the cyclocondensation reaction of the protected -acetylisatin 2a proceeded ISS Page 31

3 General Papers ARKIVC 2005 (xv) smoothly to 3-(2-acetylamino-4-fluorophenyl)-1,2-dihydroquinoxaline-2-one (3a). The hydrolysis of the acetyl group was then performed in potassium hydroxide solution. n the other 20 hand, it was not necessary to protect 7-nitroisatin (1b) by acetylation, and the cyclocondensation reaction of 1b with 1,2-diaminobenzene afforded the quinoxaline 4b in one step. The amino- derivatives 4a, 4b were cyclized to indolo[2,3-b]quinoxalines (7a, 7b) by the action of phosphorous oxychloride with catalytic amount of pyridine. ther transformations of the key amino derivatives 4 are based on the diazotization of the amino group and further intramolecular coupling with the oxo group in position 2- of the quinoxaline ring and coupling reactions on the active methylene groups of ethyl cyanoacetyl carbamate and malonodinitrile. Because of the low basicity of the amino derivatives 4 we had to use nitrosylsulfuric acid for diazotization reactions. Benzofuro[2,3-b]quinoxalines (6a, 6b) were obtained after short heating of corresponding diazonium salts, in high yields and purity. The probable intermediates of coupling reactions seem to be diazohydroxides (8) and we were able to isolate diazohydroxide 8b which is more stable than 8a. The relatively high stability of diazohydroxide 8b is probably caused by the influence of a nitro group, which can stabilize it by formation of the benzooxatriazine ring (see Scheme 2) b Scheme 2 Arylhydrazones 9a and 10a were prepared by coupling of the diazonium salt 5a with ethyl cyanoacetylcarbamate and malonodinitrile as precursors for further cyclization reactions. The arylhydrazones 9b and 10b were prepared by coupling of diazotate 8b with ethyl cyanoacetylcarbamate and malonodinitrile as precursors for further cyclization reactions. Arylhydrazones 10a, 10b were cyclized in sodium carbonate solution to 12a, 12b, and the action of hydrazine on the dinitriles 9a, 9b led to the diaminopyrazole derivatives 11a, 11b. Experimental Section General Procedures. Melting points (Boetius) are uncorrected. Infrared spectra were measured as potassium bromide disks and scanned on an ATI Unicam Genesis FTIR instrument. The MR spectra were measured in DMS-d 6 solutions on a Bruker AMX-300 spectrometer (300 Mz) ISS Page 32

4 General Papers ARKIVC 2005 (xv) with TMS as internal standard. Mass spectra were measured on a ZAB-EQ (VG Analytical Ltd., England). Elemental analyses were performed using an EA Elemental Analyzer (Fisons Instruments). RT denotes room temperature. 6-Fluoroisatin (1a). Chloral hydrate (18.0 g; mmol) and hydroxylamine sulfate (14.0 g; mmol) were dissolved in a mixture of water (120 ml) and hydrochloric acid (37 %; 8.0 ml). The solution was stirred at room temperature for 10 min. Then 3-fluoroaniline (10.0 g; 108 mmol) was added and the mixture was heated at 60 for 3 hours. After cooling to RT the mixture was left to stand overnight. The yellow precipitate was collected, washed with water and air-dried. The crude product (0.625 mol) was added portionwise with stirring to concentrated sulfuric acid (100 ml). The mixture was heated at 70 C for 30 min. After cooling to RT it was poured over crushed ice. The precipitate was collected, washed with water, diethyl ether, and airdried. Yellow crystals, yield 83.0 %, mp C, IR (KBr) ν: 3181, 3072, 1738, 1620, 1489, 1297, 1194, MR (DMS) δ: 7.00 (dd, 1, J 1 = 2.4, J 2 = 9.3, Ar); 7.19 (dt, 1, J 1 = 2.1, J 2 = 8.1, Ar); 7.87 (dd, 1, J 1 = 5.7, J 2 = 8.1, Ar); (s, 1, ). Anal. Calcd. for C F (165.13): C, 58.19;, 2.44;, Found: C, 58.12;, 2.45;, Fluoro--acetylisatin (2a). A mixture of 6-fluoroisatin (1a) (168.4 mg, 1.02 mol) and acetic anhydride (0.347 ml) was refluxed for 4 hours. After cooling to RT it was left to stand overnight. The precipitate was collected, washed with water, diethyl ether, and air-dried. Green crystals, yield 89.9 %, mp C, IR (KBr) ν: 3120, 2998, 2939, 1777, 1742, 1717, 1619, 1592, 1479, 1438, 1376, 1345, 1295, 1231, 1198, 1231, 1159, 1092, 1036, 983, 911, 839, MR (DMS) δ: 2.60 (s, 3, C 3 ), 7.23 (dt, 1, J 1 = 2.1, J 2 = 8.4, Ar), 7.88 (dd, 1, J 1 = 6.0, J 2 = 8.4, Ar), 8.03 (dd, 1, J 1 = 2.4, J 2 = 10.8, Ar). Anal. Calcd. for C F (207.16): C, 57.98;, 2.92;, Found: C, 58.01;, 3.00;, (2-Acetylamino-4-fluorophenyl)-1,2-dihydroquinoxaline-2-one (3a). The 6-fluoro-acetylisatin 2 (8.29 g; mmol) was dissolved in acetic acid (90 ml), heated to 80 C, and a solution of 1,2-diaminobenzene (4.60 g, mmol) in a mixture of water (10 ml) and acetic acid (10 ml) was added with intensive stirring. After a few minutes of stirring, a thick precipitate separated out from the solution. The reaction mixture was stirred for a further 15 minutes and cooled to RT. The precipitate was collected, washed with a small amount of acetic acid, a mixture of acetic acid and water, and finally with water. White crystals, yield 90.9 %, mp C, IR (KBr) ν: 3199, 3098, 3053, 1745, 1683, 1523, 1300, 1215, 1088, 940, 724, MR (DMS) δ: 1,97 (s, 3, C 3 ), 7.00 (dt, 1, J 1 = 2.7, J 2 = 8.7, Ar), 7.34 (d, 2, J = 7.5, Ar), 7.56 (t, 1, J = 7.2, Ar), 7.82 (m, 3, Ar), (s, 1, ), (s, 1 ). Anal. Calcd. for C F (297.29): C, 64.64;, 4.07;, Found: C, 64.39;, 4.03;, (2-Amino-4-fluorophenyl)-1,2-dihydroquinoxaline-2-one (4a). The acetyl derivative (3a) (3.76 g; mmol) was dissolved in a solution of K (6.5 g) in a mixture of ethanol (30 ml) and water (25 ml), and refluxed for a further 5 hours. Ethanol was evaporated from the reaction mixture from a water bath and the solution was acidified with acetic acid to p 5. The precipitate ISS Page 33

5 General Papers ARKIVC 2005 (xv) was collected, washed with water, and air-dried. Yellow crystals, yield 96.3 %, mp > 320 C, IR (KBr) ν: 3383, 3100, 2978, 1656, 1624, 1572, 1527, 1432, 1265, 211, 903, 839, MR (DMS) δ: 6.63 (t, 1, J = 8.7, Ar); 6.85 (dd, 1, J 1 = 2.7, J 2 = 11.7, Ar); 7.19 (s, 2, 2 ); 7.53 (m, 2, Ar); 7.78 (m, 1, Ar); 8.06 (d, 1, J = 8.1, Ar); 8.57 (m, 1, Ar); (s, 1, ). Anal. Calcd. for C F (255.25): C, 65.88;, 3.95;, Found: C, 65.78;, 3.87;, (2-Amino-3-nitrophenyl)-1,2-dihydroquinoxaline-2-one (4b). The 7-nitroisatin 20 (1b) (1.5 g; 7.8 mmol) was dissolved in acetic acid (110 ml), heated to 80 C, and a solution of 1,2- diaminobenzene (0.73 g, 6.82 mmol) in acetic acid (5 ml) was added with intensive stirring. After a few minutes of stirring, a thick precipitate separated out from the solution. The reaction mixture was stirred for the next 15 minutes and cooled to RT. The precipitate was collected, washed with a small amount of acetic acid, a mixture of acetic acid and water, and finally with water. Yellow crystals, yield 73.3 %, mp C, IR (KBr) ν: 3476, 3356, 3086, 2990, 2843, 1664, 1621, 1570, 1520, 1439, 1352, 1264, 1030, 896, MR (DMS) δ: 6.75 (t, 1, J = 15.9, Ar), 7.33 (m, 2, J = 16.2, Ar), 7.57 (m, 1, Ar), 7.81 (d, 1, J = 7.5, Ar), 7.87 (s, 2, 2 ), 7.98 (dd, 1, J 1 = 1.5, J 2 = 7.5, Ar), 8.15 (dd, 1, J 1 = 1.5, J 2 = 8.7, Ar). Anal. Calcd. for C (282.26): C, 59.57;, 3.57;, Found: C, 59.50;, 3.62;, Substituted benzofuro[2,3-b]quinoxalines (6a, 6b). General procedure Finely powdered a 2 (170.0 mg; 2.4 mmol) was added portionwise to 2 S 4 (2.6 ml; 98 %) that was pre-cooled to 0 C. After dissolving the a 2 the mixture was left to stand 2 hours at RT and then heated up to 70 C, and cooled down to 0-5 C. To this solution the corresponding amine (4a, 4b) (2.02 mmol) was added portionwise under stirring, with cooling in an ice-bath. This solution was left to stand at RT for 10 min. Then the mixture was slowly heated on a water bath to 50 C. At this temperature the product started to precipitate from the solution. The temperature of water bath was then elevated to boiling. The reaction mixture was left to stand overnight at RT. The yellow crystalline compounds were collected with suction, washed with water, and air-dried. 3-Fluorobenzofuro[2,3-b]quinoxaline (6a). White crystals, yield 83.7 %, mp C, IR (KBr) ν: 3105, 2986, 1670, 1637, 1386, 1310, 1236, 1115, 1008, 890, 827, 620, MR (DMS) δ: (m, 3, Ar), (t, 1, J = 8.7, Ar), (d, 1, J = 7.9, Ar), (dd, 2, J 1 = 5.7, J 2 = 9.0, Ar). Anal. Calcd. for C F (238.22): C, 70.59;, 2.96;, Found: C, 70.52;, 2.89;, itrobenzofuro[2,3-b]quinoxaline (6b). White crystals, yield 80.6 %, mp C, IR (KBr) ν: 3100, 1680, 1635, 1610, 1548, 1470, 1412, 1325, 840, MR (DMS) δ: 7.96 (m, 4, Ar), 8.35 (d, 1, J = 8.0, Ar), 8.60 (d, 1, J = 8.5, Ar), 9.05 (m, 1, Ar). Anal. Calcd. for C (265.23): C, 63.40;, 2.66;, Found: C, 63.32;, 2.71;, ISS Page 34

6 General Papers ARKIVC 2005 (xv) Substituted 5-indolo[2,3-b]quinoxalines (7a,7b) or their 6-tautomers. General procedure A mixture of amine (4a, 4b) (1.0 mmol) and PCl 3 (2 ml) was refluxed for 16 hours. After cooling to RT, the mixture was poured over crushed ice. The next day, the crystalline compound was collected with suction, washed with water, and dried in air. 8-Fluoro-5-indolo[2,3-b]quinoxaline (7a). Yellow crystals, yield 96.5 %, mp > 320 C (toluene), IR (KBr) ν: 3105, 2986, 1670, 1637, 1386, 1310, 1236, 1115, 1008, 890, 827, 620, MR (DMS) δ: (m, 2, Ar), (dt, 1, J 1 = 1.5, J2 = 6.9, Ar), (dt, 1, J 1 =1.5, J 2 = 6.9, Ar), (m. 2, Ar), (dd, 1, J 1 = 1.8, J 2 = 8.4, Ar), (s, 1, ). Anal. Calcd. for C F (237.24): C, 70.88;, 3.40;, Found: C, 70.89;, 3.20;, itro-5-indolo[2,3-b]quinoxalines (7b). Yellow crystals, yield 89.3 %, mp > 320 C (toluene), IR (KBr) ν: 3100, 1680, 1635, 1610, 1548, 1470, 1412, 1325, 840, MR (DMS) δ: (d, 1, J = 8.4, Ar), (t, 1, J = 6.9, Ar), (m, 2, Ar), (d, 1, J = 8.2, Ar), (d, 1, J = 8.4, Ar), (d, 1, J = 2.1, Ar), (s, 1, ). Anal. Calcd. for C (264.24): C, 63.64;, 3.05;, Found: C, 63.51;, 2.98;, [(2-ydroxydiazenyl)-3-nitrophenyl]-1,2-dihydroquinoxaline-2-one (8b). Finely powdered a 2 (170.0 mg; 2.4 mmol) was added portionwise to 2 S 4 (2.6 ml; 98 %) pre-cooled to 0 C. After dissolving the a 2 the mixture was left to stand 2 hours at RT and then heated up to 70 C and cooled down to 0-5 C. To this solution the amine (4b) (570.2 mg; 2.02 mmol) was added portionwise under stirring, with cooling in an ice-bath. The solution was left to stand for 30 min in the ice bath and then was added portionwise during 10 min to a stirred mixture obtained by dissolving C 3 Ca (24 g) in warm water (130 ml), cooling on an ice bath, and adding crushed ice. The next day, a crystalline compound was collected with suction, washed with water, and dried in air. Yellow crystals, yield 97.2 %, mp C, IR (KBr) ν: 3210, 3055, 2922, 1696, 1611, 1530, 1497, 1432, 1347, 1146, 1105, 1041, 818, MR (DMS) δ: 7.15 (dd, 1, J1 = 1.5, J 2 = 1.5, Ar), 7.21 (m, 1, Ar), 7.30 (m, 1, Ar), 7.84 (m, 2, Ar), 8.12 (dd, 1, J 1 =1.5, J 2 =1.5, Ar), 8.41 (dd, 1, J 1 =1.5, J 2 =1.5, Ar). Anal. Calcd. for C (311.26): C, 54.02;, 2.91;, Found: C, 53.96;, 2.79;, MS (ESI, m/z (rel. %)): (100) (M+1) +. 5-Fluoro-2-(3-oxo-3,4-dihydroquinoxaline-2-yl)-phenylhydrazonomalonodinitrile (9a). Finely powdered a 2 (170.0 mg; 2.4 mmol) was added portionwise to 2 S 4 (2.6 ml; 98 %) that was pre-cooled to 0 C. After dissolving the a 2 the mixture was left to stand 2 hours at RT and then heated to 70 C and cooled down to 0-5 C. To this solution the amine (4a) (515.6 mg; 2.02 mmol) was added portionwise under stirring. The solution was left to stand for 30 min in an ice bath and then was added portionwise during 10 min to a stirred mixture obtained by dissolving malonodinitrile (0.202 g; 2.02 mmol) in warm water (130 ml), cooling on an ice bath, adding C 3 Ca (24.0 g) and crushed ice (5 g). The next day, the crystalline compound was collected with suction, washed with water, and dried in air. Yellow crystals, yield 91.5 %, mp C, IR (KBr) ν: 3005, 2893, 2858, 2228, 1657, 1587, 1474, 1433, 1293, 1246, 1210, ISS Page 35

7 General Papers ARKIVC 2005 (xv) , 755, MR (DMS) δ: 6.59 (m, 1, Ar), 6.89 (dd, 1, J 1 =2.6, J 2 =11.0, Ar), 7.53 (m, 2, Ar), 7.78 (m, 1, Ar), 8.10 (d, 1, J = 8.5, Ar), 8.58 (m, 1, Ar), (s, 1, ). Anal. Calcd. for C F (332.3): C, 61.45;, 2.73;, Found: C, 61.33;, 2.77;, itro-2-(3-oxo-3,4-dihydroquinoxaline-2-yl)-phenylhydrazonomalonodinitrile (9b). To the mixture of diazotate (8b) (150.0 mg, 0.48 mmol) in a mixture of water:acetonitrile (30 ml; 1:1) ethyl cyanoacetyl carbamate ( mg, 0.72 mmol) was added and the reaction mixture was stirred for a further 24 hours. The next day, the crystalline compound was collected with suction, washed with water, and dried in air. Yellow crystals, yield 87.5 %, mp C, IR (KBr) ν: 3322, 3094, 2843, 2224, 1664, 1580, 1535, 1515, 1356, 1246, MR (DMS) δ: 7.34 (m, 2, Ar), 7.47 (t, 1, J = 15.9, Ar), 7.56 (m, 1, Ar), 7.78 (dd, 1, J 1 = 0.9, J 2 = 8.1, Ar), 7.85 (dd, 1, J 1 = 1.5, J 2 = 7.8, Ar), 8.01 (dd, 1, J 1 = 1.5, J 2 = 8.1, Ar), (s, 1, ). Anal. Calcd. for C (359.3): C, 56.83;, 2.52;, Found: C, 56.77;, 2.44;, Ethyl 5-fluoro-2-(3-oxo-3,4-dihydroquinoxaline-2-yl)-phenylhydrazonocyanoacetyl carbamate (10a). Finely powdered a 2 (170.0 mg; 2.4 mmol) was added portionwise to 2 S 4 (2.6 ml; 98 %) that was pre-cooled to 0 C. After dissolving the a 2 the mixture was left to stand 2 hours at RT and then heated up to 70 C and cooled down to 0-5 C. To this solution, amine (4a) (515.6 mg; 2.02 mmol) was added portionwise under stirring. The solution was left to stand for 30 min in an ice bath and then was added portionwise during 10 min to a stirred mixture obtained by dissolving ethyl cyanoacetylcarbamate (0.42 g; mmol) in warm water (130 ml), cooling on an ice bath, adding C 3 Ca (24.0 g) and crushed ice (5 g). The next day, a crystalline compound was collected with suction, washed with water, and dried in air. Yellow crystals, yield 92.0 %, mp C, IR (KBr) ν: 3477, 3284, 3088, 3002, 2214, 1773, 1737, 1656, 1617, 1578, 1526, 1483, 1434, 1372, 1301, 1270, 1205, 1167, 1100, 1044, MR (DMS) δ: 1.06 (t, 3, J = 7.2, C 3 ), 4.08 (q, 2, J 1 = 5.7, J 2 = 13.5, C 2 ), 7.33 (m, 2, Ar), 7.57 (m, 2, Ar), 7.79 (m, 2, Ar), 8.09 (d, 1, J = 9.0, Ar), (s, 1, ), (s, 1, ). Anal. Calcd. for C F (422.38): C, 56.87;, 3.58;, Found: C, 56.67;, 3.59;, Ethyl 6-nitro-2-(3-oxo-3,4-dihydroquinoxaline-2-yl)-phenylhydrazonocyanoacetyl carbamate (10b). To the mixture of 3-[(2-hydroxydiazenyl)-3-nitrophenyl]-1,2-dihydro-quinoxaline-2-one (8b) (150.0 mg, 0.48 mmol) in a mixture of water:acetonitrile (1:1) the malonodinitrile (47.5 mg, 0.72 mmol) was added and the reaction mixture was stirred for a further 24 hours. The next day, the crystalline compound was collected with suction, washed with water and dried in air. Yellow crystals, yield 80.9 %, mp C, IR (KBr) ν: 3360, 3080, 2829, 2214, 1789, 1669, 1533, 1503, 1293, 1188, 1028, 933, MR (DMS) δ: 1.10 (t, 3, J = 7.2, C 3 ); 3.81 (q, 2, J 1 = 6.9, J 2 = 14.1, C 2 ); 7.32 (m, 2, Ar); 7.57 (m, 2, Ar); 7.81 (dd, 1, J 1 = 1.2, J 2 = 8.1, Ar); 8.04 (dd, 1, J 1 = 1.2, J 2 = 7.9, Ar); 8.2 (dd, 1, J 1 = 1.2, J 2 = 8.1, Ar); 9.31 (s, 1, ); (s, 1, ). Anal. Calcd. for C (449.38): C, 53.46;, 3.36;, Found: C, 53.38;, 3.42;, ISS Page 36

8 General Papers ARKIVC 2005 (xv) [Substituted-2-(3,5-diamino-pyrazol-4-yl)-azo]-phenyl-1,2-dihydroquinoxalin-2-one (11a, 11b). General procedure A suspension of the corresponding hydrazone (9a, 9b) (1 mmol), hydrazine hydrate (0.1 ml; 2.0 mmol; 99 %) and methanol (35 ml) was heated for 10 minutes. After cooling to RT the solution was acidified with acetic acid (0.3 ml). The reaction mixture was crystallized with charcoal. The filtrate was evaporated (40 C; 20 mm g) and the solid was mixed with water (20 l). The next day the compounds were collected with suction, washed with water, and dried in air. 3-[4-Fluoro-2-(3,5-diamino-pyrazol-4-yl)-azo]-phenyl-1,2-dihydroquinoxalin-2-one (11a). Yellow crystals, yield 84.9 %, mp C (ethanol), IR (KBr) ν: 3024, 2814, 1761, 1721, 1654, 1537, 1223, 774, MR (DMS) δ: 4.12 (s, 2, 2 ), 5.91 (s, 2, 2 ), 7.49 (m, 3, Ar), 7.60 (m, 2, Ar), 7.70 (d, 1, J = 9.0, Ar), 7.96 (m, 1, Ar), (s, 1, ). Anal. Calcd. for C F (364.34): C, 56.04;, 3.60;, Found: C, 55.98;, 3.51;, [3-itro-2-(3,5-diamino-pyrazol-4-yl)-azo]-phenyl-1,2-dihydroquinoxalin-2-one (11b). Yellow crystals, yield 73.9 %, mp C (ethanol), IR (KBr) ν: 3463, 3375, 1674, 1617, 1561, 1522, 1505, 1395, 1303, 1226, 1121, MR (DMS) δ: 4.22 (s, 2, 2 ); 5.99 (s, 2, 2 ); 7.31 (m, 2, Ar), 7.42 (t, 1, J = 15.6, Ar), 7.53 (m, 1, Ar), 7.66 (dd, 1, J 1 = 1.2, J 2 = 7.5, Ar), 7.75 (dd, 1, J1 = 1.2, J 2 = 8.4, Ar), 7.93 (dd, 1, J 1 = 1.5, J 2 = 7.8, Ar), (s, 1, ), (s, 1 ). Anal. Calcd. for C (391.35): C, 52.18;, 3.35;, Found: C, 52.19;, 3.40;, [Substituted-2-(3-oxo-3,4-dihydroquinoxalin-2-yl)-phenyl]-3,5-dioxo-2,3,4,5-tetrahydro- [1,2,4]-triazine-6-carbonitrile (12a, 12b). General procedure A mixture of hydrazone (10a, 10b) (1.0 mmol), a 2 C 3 (120.0 mg) and water (10 ml) was heated on a boiling water bath until a solution was formed and then for an additional 15 minutes. After cooling to RT the solution was allowed to cool down and acidified with Cl (37 %) to p 1. After several hours, the crystalline solid was collected with suction, washed with a little water, and dried in air. 2-[2-(3-xo-3,4-dihydroquinoxalin-2-yl)-5-fluorophenyl]-3,5-dioxo-2,3,4,5-tetrahydro- [1,2,4]-triazine-6-carbonitrile (12a). White crystals, yield 79.7 %, mp C (ethanol), IR (KBr) ν: 3388, 3256, 3098, 2945, 2242, 1640, 1600, 1564, 1500, 1427, 1366, 1259, 1148, 1007, 857, 756, MR (DMS) δ: 7.39 (m, 2, Ar), 7.53 (m, 3, Ar), 7.60 (d, 1, J = 8.7, Ar), 7.90 (m, 1, Ar), 9.86 (s, 1, ), (s, 1, ). Anal. Calcd. for C F (376.31): C, 57.45;, 2.41;, Found: C, 57.50;, 2.43;, [2-(3-xo-3,4-dihydroquinoxalin-2-yl)-6-nitrophenyl]-3,5-dioxo-2,3,4,5-tetrahydro- [1,2,4]-triazine-6-carbonitrile (12b). White crystals, yield 80.0 %, mp C (ethanol), IR (KBr) ν: 3455, 3369, 2244, 1699, 1650, 1558, 1390, 1300, 1225, 1121, 748, MR (DMS) δ: 7.40 (m, 2, Ar), 7.56 (t, 1, J = 7.6, Ar), 7.78 (d, 1, J = 8.8, Ar), 7.98 (m, 3, Ar), (s, 1, ). Anal. Calcd. for C (403.31): C, 53.61;, 2.25;, Found: C, 53.49;, 2.19;, ISS Page 37

9 General Papers ARKIVC 2005 (xv) Acknowledgements We are grateful to the Ministry of Education, Youth and Sport of the Czech Republic, for the grant MSM References 1. For the previous paper, see ref Benkli, K.; Demirayak, S.; Gundogdu-Karaburn,.; Kiraz.; Iscan G.; Ucucu U. Indian. J. Chem. 2004, 43B, Bertinaria, M.; Galli, U.; Sorba, G.; Fruttero, R.; Gasco, A.; Brencliaglia, M. I.; Scaltrito, M. M.; Dubini, F. Drug Dev. Research 2003, 60, Burli, R. W.; Jones, P.; McMinn, D.; Le, Q.; Duan, J.X.; Kaizerman, J. A.; Difuntorum, S. Moser,. E. Bioorg. Med. Chem. 2004, 14, Farghaly, A. R. J. Chin. Chem. Soc. 2004, 51, Pruhomme, M.; ugon, B.; Anizon, F.; ickman, J.; Pierre, A.; Golsteyn, R.; Renard, P.; Pfeiffer, B. Fr. Demand 2004, 71, Reddy, P..; Reddy, Y. T.; Rao, M. K.; Rajitha, B. eterocyclic Commun. 2003, 9, Chennama, B.; Selvam, P.; Jaswanth, A.; Ruckmani, K.; Vijayakumar, A. Anala Res. Bull. 2003, 23, Kim, D. K.; Kim, J.; Park,. J. Bioorg. Med. Chem. 2004, 14, Li,.Y.; Wang, Y.; Yan, L.; Campbell, R. M.; Anderson, B. D.; Wagner, J. R.; Yingling, J. M. Bioorg. Med. Chem. 2004, 14, Price, D. A.; Selby, M. D.; Stupple, P. A. PCT Int. Appl. 2004, Sriram, D.; Bal, T. R; Yogeeswari, P. Bioorg. Med. Chem. 2004, 12, irai,.; Kawanishi,.; irose, M.; Sugimoto, T.; Kamijyo, K.; Shibta, J.; Masutani, K. PCT Int. Appl. 2004, Stiles, T.W.; Mceil, D. Tetrahedron Lett. 1990, Kryštof, V.; Cankař, P.; Fryšová, I.; Slouka, J.; tyepka, M.; Rolčík, J.; Látr, A.; Strnad, M. Chem. Lett. 2004, 98, Wiedermannová, I.; tyepka, M.; Stýskala, J.; Slouka J. ARKIVC 2003, (xv), laváč, J.; Buchtík, R.; Slouka, J.; radil, P.; Wiedermannová, I. ARKIVC 2003, (i), Joshi, K. C.; Patni, R.; Chand, P.; Sharma, V.; Bhattacharya, S. K.; Rao, Y. V. Pharmazie 1984, 39, Yamagishi, Y.; zaki, K. I.; Asao, M.; Shimizu, R. J. Med Chem. 1992, 35, Buchman, E. R. J. Am. Chem. Soc. 1947, 69, 380. ISS Page 38